Scientific investigation on antibacterial, antioxidant, cytotoxic effects and TLC bioautography of Terminalia schimperiania stem bark extracts.

Abstract

Objectives: Terminalia schimperiana Hochst, belonging to the Combretaceae family, is known for its ethnomedicinal values, particularly in treating various diseases in Africa. This study aimed to investigate the antibacterial, antioxidant, and cytotoxic properties of T. schimperiana stem bark extracts, with a specific focus on assessing their bioactive potential and identifying active compounds via TLC bioautography.

Methods: The in vitro antimicrobial activity was assessed using the agar well diffusion method against selected clinical strains. Antioxidant activity was evaluated using several methods including free radical scavenging, ferrous ion chelation assays and total phenolic content analysis. The cytotoxicity of the extracts was assessed using MTT assay towards Raw 264.7 and Vero cell lines.

Results: All extracts demonstrated significant antibacterial activity against the bacteria tested, with inhibition zones (IZ) ranging from 6.50 ± 0.71 to 15.50 ± 0.71 mm and minimum inhibitory concentrations (MIC) ranging from 1.95 to 1,250 μg/mL. The hydroethanolic extract exhibited strongest antioxidant activities with EC₅₀ values of 188.50; 245.30, and 281.50 μg/mL for DPPH; ABTS, ferrous ion chelation assays respectively, and a high content of phenolic compounds (101.67 ± 2.97 µgEFA/mg DW). Importantly, no cytotoxic effects were observed on Raw 264.7 and Vero cell lines. HPTLC analysis identified alkaloids and phenolic compounds in both aqueous and hydroethanolic extracts.

Conclusions: These findings indicate T. schimperiana provides a wealth of bio-compounds that can be utilised in the pharmaceutical industry as antibacterial and antioxidant agents to combat antibiotic resistance.